1. Technical Field
Embodiments of the present disclosure relate to an apparatus and a method for compensating a torque of a motor-driven power steering system, and more particularly, to an apparatus and a method for compensating a torque of a motor-driven power steering system, for improving a steering feel of a driver.
2. Related Art
A motor-driven power steering (MDPS) system of a vehicle is an apparatus which facilitates steering by providing a portion of a steering torque that a driver should apply to a steering wheel when steering the vehicle, by using an auxiliary power source.
A steering intention of the driver is sensed through a torque sensor which is directly coupled to the steering wheel, and a corresponding signal is transferred to the MDPS system. The MDPS system drives an electric motor to provide an appropriate force in consideration of a current vehicle speed, etc., thereby assisting in the steering force of the driver. The MDPS system reduces a force required to the driver by assisting a large force when the vehicle is parked or stopped or is driven at a low speed, and maintains the stability of a vehicle body by assisting only a small force when the vehicle is driven at a high speed.
Meanwhile, in the vehicle equipped with such an MDPS system, a system for improving a steering feel that is felt by the driver through the steering wheel, depending on a steering state of the driver, is demanded. In particular, in the case where the driver reverses steering, a problem may be caused in that an instantaneous load is generated due to friction, inertia or lack of responsiveness of an MDPS motor in a mechanism provided to the MDPS system and thereby the driver feels a sticky steering feel. Moreover, in the case where the driver holds the steering wheel, a problem may be caused in that fine vibration and noise are transferred through the steering wheel due to noise in a torque sensor and a current sensor which senses the current of the MDPS motor and thereby a steering feel of the driver deteriorates.
A background art of the present disclosure is disclosed in Korean Unexamined Patent Publication No. 2005-0046726 (dated May 18, 2005).